1. Field of Invention
This invention relates to an adapter for automatically dispensing any type of scented, colored, cleansing or disinfecting liquid chemical directly into the bowl of a toilet installed in a recreational vehicle (RV). The toilet would be a typical RV toilet connected to a pressurized fresh water supply. Such recreational vehicles include motorhomes, travel trailers and marine craft. This invention is adaptable to both existing RV toilets and newly purchased RV toilets.
2. Description of Prior Art
Contemporary RVs have toilet systems which retain their waste water inside large compartments called holding tanks. Usually, holding tanks are installed directly beneath the RV toilet, immediately under the toilet room deck. With the toilet situated directly above the holding tank, it can flush directly into the holding tank without the use of a soil trap, thereby using a minimum amount of water in the process. Usually there is merely a vertical soil pipe which carries the waste from the RV toilet to the holding tank. Holding tanks are normally large enough to store waste water for a long enough duration until the owner finds it convenient to release the waste at an approved sewage dumping facility.
Even though the implementation of holding tanks has been very successful, the addition of chemicals to a holding tank has always been necessary for deodorizing the holding tank and enhancing the decomposition of waste. There is a possibility of the holding tank interior getting soiled and smelly if the owner neglects to add the chemicals before using the RV toilet. Usually, the additive chemicals are pre-measured liquids or powders, and are sent to the holding tank by flushing them directly down the toilet. In other instances, the owner needs to measure an amount of chemical before flushing it down the toilet. Sometimes, the RV gets used only for a small outing and then much of the chemical gets wasted from subsequent emptying of the holding tank when returning home.
Understandably, holding tanks can produce noxious odors which will migrate upward through the toilet bowl and into the RV interior spaces. However, RV toilets are internally constructed to seal shut at the base of the toilet bowl, thereby sealing off odors from the holding tank. Commonly, RV owners take advantage of the toilet's ability to seal at its base by leaving a preferred amount of water in the bowl. The ability of the RV toilet bowl to be prefilled with fresh water, much like a common household toilet, continues to give rise to the possibility of having colored, deodorized water standing in the bowl. Chemically-treated fresh water in the bowl of an RV toilet contributes to deodorizing both the RV toilet and bathroom. The same chemical additive would then enhance the overall treatment of waste in the holding tank. An understanding of the primary differences between household toilets and RV toilets will yield an appreciation as to why chemically treated additives in RV toilet bowls are not commonly found.
RV toilets are usually fitted with a combination-control lever which allows the option of either pre-filling the toilet bowl with the desired amount of water, or the dual-action of releasing toilet waste to the holding tank while allowing inlet-fresh water to rinse the toilet bowl. Because they are water frugal devices, RV toilets are not fitted with flush-water tanks behind the bowl as found on household toilets. The existence of flush-water tanks has made the use of water coloring, deodorizing and sanitizing chemicals convenient and safe for household toilets. By design, household toilet flush-water tanks maintain a safety air-gap between the water standing in the flush-water tank and the water in the supply line which prefills the tank. The air-gap, along with an overflow tube which dumps excess water directly to the toilet bowl, ensures against the possibility of chemical additives back-flowing into the household fresh water supply lines. Chemicals readily usable in household toilet flush-water tanks are found in dissolvable cake or tablet form.
Since RV toilets are not designed with flush-water tanks, such tank-installed chemical accessories for pre-deodorizing, coloring, and sanitizing toilet flush water are not employable. Consequently, with the absence of a flush-water tank, prefilling the RV toilet bowl with aromatic, colored, sanitizing chemicals has been a challenge to inventors.
Prior art remedies have mainly focused on the insertion of chemical additives into the water carried by the RV toilet inlet plumbing. The most popular technique has involved the use of chemical-mixing canisters which become pressurized by the RV fresh water supply line. Using the technique of inserting chemicals into the toilet water inlet line gives rise to the danger of chemical contamination of the RV fresh water supply. To counteract this possibility, prior art inventions have made use of one-way check valves installed in the fresh water supply tubing, upstream of the chemical canister. However, the eventual failure of the one-way check valve, due to hard water buildup and degradation of internal one-way check valve components, could cause serious physical harm to the RV occupants.
The crafty implementation of combining a safety air-gap as found in household toilet flush-water tanks, along with the additional safety assurance of a one-way check valve is exhibited in U.S. Pat. No. 4,841,578 issued to Mr. Al Mercer (1989). Unfortunately, his invention requires severing the toilet inlet water line and installing a bulky, multi-functional canister and trap assembly. Usually, RV bathrooms are small and space for such bulky components is seldom available; especially behind the toilet.
Another respectable invention which inserts chemical additives into the water entering the toilet is presented in U.S. Pat. No. 4,262,372 awarded to Donald F. Ryder (1981). Mr. Ryder's invention is typical of prior art which modifies the plumbing system and specifies the installation of a one-way check valve to keep the chemical concentrate from contaminating the RV fresh water source.
Also of merit, is U.S. Pat. No. 4,873,727 awarded to Donald A. Homan (1989) which exhibits a variation of the chemical mixing chamber. As usual, his chemical mixing chamber is installed into the toilet water inlet line. Mr. Homan's invention also utilizes a variety of one-way check valve referred to as an "anti-siphon valve". In this application, the anti-siphon valve is used as a performance enhancement rather than that of safety. Mr. Homan's invention was designed strictly for a marine toilet using sea water for its flush cycle, making a safety-check valve unnecessary. In addition to being limited to marine use, Mr. Homan's invention shares limitations in common with those of Mr. Mercer's and Mr. Ryder's.
All prior art cited utilize a variety of mixing containers which allow the combining of toilet flush water with concentrated chemicals. Unfortunately, this technique will produce non-linear concentrations of additive throughout the life cycle of each chemical replenishment, and is the effect of continued dilution of the chemical by water passing through the canister.
A later patent, U.S. Pat. No. 5,142,707 awarded to Frederick Prue (1992), specifies the installation of a chemical injection unit with numerous fluid gate valves. This invention is limited to marine craft toilets designed with salt-water flushing systems, requires through-hull component installations, and has many expensive, space-consuming parts.
Typical with all cited prior art is the lack of control offered to the toilet user. If, for example, the user finds the deodorization too strong, provisions for variably controlling the concentration of chemical additive are rarely furnished. Additionally, none of the prior art cited offers the convenience of a simple on/off switch.
Consequently, a new approach is needed for the design of an RV toilet chemical dispenser. Such an approach should make use of newer technology in fulfilling the above stated need for deodorizing, sanitizing, coloring, and generally treating toilet flush water in all classes of RVs.